Roof-mounted occupant safety system for 360 degree protection

TECHNICAL FIELD

The present invention relates generally to occupant safety systems and, in particular, relates to occupant safety systems including roof-mounted airbags for vehicles, such as autonomous vehicles, that have seats that can rotate.

BACKGROUND

It is known to provide an inflatable vehicle occupant protection device, such as an airbag, for helping to protect an occupant of a vehicle. One particular type of airbag is a frontal airbag inflatable between an occupant of a front seat of the vehicle and an instrument panel of the vehicle. Frontal airbags can be driver airbags or passenger airbags. When inflated, the driver and passenger airbags help protect the occupant from impacts with parts of the vehicle such as the instrument panel and/or a steering wheel of the vehicle.

Other types of airbags include side airbags and curtain airbags, both of which are inflatable between a seated occupant and a side structure of the vehicle. When inflated, the side and curtain airbags help protect the occupant from impacts with the side structure of the vehicle.

There are trends in the auto industry to make vehicles more spacious. Styling has been making the instrument panel smaller and thus farther away from the occupant. Looking further into the future, driverless, autonomous vehicles are even more spacious. Autonomous vehicles have been contemplated for some time, and now their adaption on a large scale is approaching. Autonomous vehicles can eliminate some of the vehicle structure that is common to current vehicle architecture.

With these realities as a backdrop, the paradigm of occupant safety systems must shift. In the past, the necessity of a vehicle operator/driver lent to a somewhat standard vehicle passenger cabin configuration. In the U.S., the driver is a front seat, left side, forward facing occupant within reach of the vehicle controls and instrumentation (steering wheel, pedals, instrument panel, console, etc.). This driver configuration helps dictate the layout of the remainder of the vehicle—front seat, forward-facing passenger-side occupant, rear seat (second row, third row, etc.) forward-facing occupants. Accordingly, in the past, occupant safety systems were typically designed with this passenger cabin layout and the associated occupant positions and orientations in mind.

The autonomous vehicle eliminates the vehicle operator/driver. As a result, this also eliminates the necessity of vehicle passengers being positioned and oriented in the conventional manner described above. Vehicle manufacturers are free to utilize passenger cabin space as they see fit without being constrained to predetermined passenger arrangements, such as all forward-facing occupants, or vehicle structural configurations, such as steering wheel/instrument panel configurations, center console configurations, foot well, pedal controls, etc.

This presents the challenge of not only where to locate airbag systems, but also finding a reaction surface against which to position the airbag so that it can absorb impacts. Typically, instrument panel and steering wheel mounted frontal airbags utilize those structures as a reaction surface against which the airbag rests so that it can oppose, cushion, and absorb the impact energy of an impacting occupant and provide a desired ride-down effect. In the autonomous vehicles, however, the vehicle may not have an instrument panel or steering wheel at all, and the occupants can be positioned and oriented outside the traditional manner. This can make it difficult or impossible to utilize traditional structures in the vehicle as reaction surfaces.

SUMMARY

The invention relates to an occupant safety system in which an occupant restraint in the form of an airbag is mounted on the vehicle roof above an occupant seating position. The airbag is deployable downward from the vehicle roof and is configured to provide 360-degree protection. The airbag at least partially encircles or surrounds the occupant and a portion of the seat, e.g., the seatback, so that the seat and the roof can serve as a reaction surface for supporting the airbag. The airbag can therefore cushion the occupant and absorb impact forces resulting from a vehicle crash.

According to one aspect, an airbag helps protect an occupant of a vehicle having a roof and a cabin with a seat for the occupant. The airbag includes an upper portion for being mounted to a vehicle roof, a lower portion having a ring-shaped configuration configured to encircle the occupant and a seatback of the vehicle seat when deployed, and at least one pillar connecting the lower portion to the upper portion.

According to another aspect, the lower portion encircling the seatback can configure the lower portion to utilize the seatback as a reaction surface for supporting the lower portion against movement in response to an impacting occupant.

According to another aspect, alone or in combination with other aspects, the pillars can provide fluid communication from the upper portion to the lower portion and are configured to direct inflation fluid from the upper portion to the lower portion.

According to another aspect, alone or in combination with other aspects, the pillars can be spaced from each other. The airbag can also include windows defined between the pillars and bounded at a lower extent by the lower portion of the airbag.

According to another aspect, alone or in combination with other aspects, the airbag can be configured to allow the occupant to lean and/or bend forward and partially pass through the windows in response to a vehicle crash. The lower portion can be configured to conform to the leaned and/or bent forward occupant.

According to another aspect, alone or in combination with other aspects, the pillars can be configured to position the window in front of a forward-facing vehicle seat.

According to another aspect, alone or in combination with other aspects, the airbag can include four pillars spaced about the lower portion and defining four windows.

According to another aspect, alone or in combination with other aspects, the pillars can be configured to position one window in front of a forward-facing vehicle seat, one window outboard of the forward-facing vehicle seat, one window inboard of the forward-facing vehicle seat, and one window rearward of the forward-facing vehicle seat.

According to another aspect, alone or in combination with other aspects, the pillars can be interconnected to the lower portion at positions that are lateral to a seating surface of the vehicle seat when the airbag is deployed. The pillars can thereby be configured so that an occupant that moves laterally relative to the vehicle seat in response to a vehicle crash is received in a junction where a pillar interconnects with the lower portion.

According to another aspect, alone or in combination with other aspects, in response to receiving the laterally moving occupant, the lower portion can restrain and cushion the occupant primarily against forward movement relative to the vehicle seat. The pillar can restrain and cushion the occupant primarily against lateral movement relative to the vehicle seat.

According to another aspect, alone or in combination with other aspects, the lower portion can have a generally toroidal configuration, a generally circular cross-section, or a generally polygonal cross-section.

According to another aspect, alone or in combination with other aspects, an airbag module can include the airbag, an inflator that is actuatable to produce inflation fluid for inflating and deploying the airbag, and a housing for supporting the airbag and inflator on the vehicle roof.

According to another aspect, alone or in combination with other aspects, a vehicle safety system can include the airbag module. The vehicle safety system can further include a sensor for sensing the occurrence of an event for which deployment of the airbag is desired and producing a signal indicative thereof, and a controller connected to the sensor and, in response to receiving the signal, actuating the inflator to inflate and deploy the airbag.

Other objects and advantages and a fuller understanding of the invention will be had from the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idref="DRAWINGS">FIG. 1</figref> is a side view of a vehicle including an example roof-mounted, occupant safety system, illustrating the system in a non-deployed condition.

<figref idref="DRAWINGS">FIG. 2</figref> is a side view of the vehicle of <figref idref="DRAWINGS">FIG. 1</figref>, illustrating the system in a deployed condition.

<figref idref="DRAWINGS">FIG. 3</figref> is a perspective illustration of an occupant restraint in the form of an airbag that forms a portion of the system of <figref idref="DRAWINGS">FIGS. 1 and 2</figref>.

<figref idref="DRAWINGS">FIGS. 4 and 5</figref> are front views illustrating the occupant safety system in non-deployed and deployed conditions, respectively, in a crash scenario resulting in forward occupant movement.

<figref idref="DRAWINGS">FIG. 6</figref> is a front view illustrating the occupant safety system in a deployed condition in a crash scenario resulting in angular occupant movement.

<figref idref="DRAWINGS">FIG. 7</figref> is a front view illustrating the occupant safety system in a deployed condition in a crash scenario involving an occupant in a side-facing seat.

<figref idref="DRAWINGS">FIG. 8</figref> is a front view illustrating the occupant safety system in a deployed condition in a crash scenario involving an occupant in an angular-facing seat.

DETAILED DESCRIPTION

The present invention relates generally to occupant safety systems including occupant restraints. In particular, relates to occupant safety systems including roof-mounted airbags in a vehicle where the occupants and the seats that they occupy can face in directions other than the typical forward facing vehicle seat. <figref idref="DRAWINGS">FIGS. 1-5</figref> illustrate an example occupant safety system <b>100</b> for protecting an occupant <b>10</b> of a vehicle <b>20</b>. The occupant <b>10</b> is seated on a vehicle seat <b>30</b> in a passenger cabin <b>50</b> of the vehicle <b>20</b>. For purposes of reference in describing the position of the occupant <b>10</b> and other structures in or relative to the vehicle <b>20</b>, arrows <b>24</b> are shown in <figref idref="DRAWINGS">FIGS. 1 and 4</figref> to indicate fore/forward and aft/rearward longitudinal directions in the vehicle, along or parallel to a vehicle centerline <b>22</b>. Left and right lateral directions in the vehicle are also shown by arrows <b>26</b>. The left and right directions are viewed from the perspective of looking in the fore direction in the vehicle, and extend perpendicular to the centerline <b>22</b>.

In this description, reference can also be made to inboard and outboard directions in the vehicle <b>20</b>. The inboard direction is meant to refer to a lateral direction toward the vehicle centerline <b>22</b>. The outboard direction is meant to refer to a lateral direction away from the vehicle centerline <b>22</b>. Therefore, it will be appreciated that the lateral direction associated with inboard and outboard depend on the perspective from which those directions are observed. For example, from a driver side seating position, inboard is the right lateral direction and outboard is the left lateral direction. Conversely, from a passenger side seating position, inboard is the left lateral direction and outboard is the right lateral direction. Inboard and outboard for the forward-facing, driver side seated occupant <b>10</b> are shown in <figref idref="DRAWINGS">FIG. 4</figref>.

The vehicle <b>20</b> can be an autonomous vehicle, in which case the passenger cabin <b>50</b> can be without operator controls, such as a steering wheel, pedals, instrumentation, center console, etc. Accordingly, the instrument panel (not shown) can be reduced in size or removed altogether in order to maximize the space in the passenger cabin <b>50</b>. The seating arrangements shown and described herein can therefore be illustrative of any seating position in the vehicle <b>20</b> (e.g., driver side/passenger side, 1^strow, 2^ndrow, 3^rdrow, etc.). In <figref idref="DRAWINGS">FIGS. 1-5</figref>, the passenger <b>10</b> is seated on a vehicle seat <b>30</b> on a left (viewed facing forward in the vehicle) or driver side of the vehicle, adjacent the vehicle side structure <b>52</b>, which can include one or more side windows <b>54</b> and one or more pillars <b>56</b>.

In the open configuration of the passenger cabin <b>50</b>, the vehicle seats <b>30</b> can be configured, positioned, and arranged in a variety of manners, not constrained by the need to facilitate the conventional vehicle driver/operator arrangement. For example, the seats <b>30</b> can be arranged in rows that are forward-facing, in a manner similar to that of conventional automobiles. Alternatively, the seats <b>30</b> can be arranged in rows so that the occupants of the rows face each other, such as forward and rearward rows that face each other, and/or left and right rows that face inboard toward each other. Each seat <b>30</b> is fitted with a seatbelt <b>42</b> for restraining its occupant <b>10</b>.

Individually, the seats <b>30</b> can be mounted on a swivel base <b>32</b>, which allows the seats to rotate about a vertical seat axis <b>40</b>. This can offer 360 degrees of rotation, where the occupant <b>10</b> can select the desired seat orientation. Alternatively, the seats <b>30</b> can be configured for indexed rotational positions, such as 15-degree increments. The rotational position of the seats <b>30</b> can thus be selected, for example, to provide the forward/rearward or left/right facing each other seating configurations described above. In this description, for the sake of clarity in explanation, the rotational position is considered to be at zero degrees in the forward-facing position, parallel to the vehicle centerline <b>22</b>. Rotational positions can therefore be described in terms of degrees and direction, such as 15 degrees inboard, 90 degrees outboard, 180 degrees rearward, etc.

The seats <b>30</b> include a seat bottom <b>34</b>, mounted on the seat base <b>32</b>, for supporting the seated occupant <b>10</b>. A seatback <b>36</b> extends vertically from the seat bottom <b>34</b>. The seatback <b>36</b> can have a reclining configuration in which an angle of reclination can be selected by the occupant <b>10</b>. The seat can also include a headrest (not shown) that extends upward from the seatback <b>36</b>.

For the conventional, forward-facing seating arrangement of <figref idref="DRAWINGS">FIGS. 1-5</figref>, in the event of a frontal crash, the occupant <b>10</b> is restrained by the seatbelt <b>42</b>. Additional restraints are, however, desirable to cushion and support torso, head, neck, and other body parts. In a conventional vehicle, this additional protection would typically be provided, at least for front row occupants, by instrument panel/steering wheel mounted airbags. In the autonomous vehicle <b>20</b> of <figref idref="DRAWINGS">FIGS. 1-5</figref>, however, the instrument panel can be reduced in size and/or removed altogether. Control interfaces for climate controls, GPS, navigation, entertainment, etc. can, for example, be provided in a center console area of the vehicle <b>20</b> located between the seat rows.

Because the front row seats need not be in close proximity to the instrument panel or the area where an instrument panel would normally reside, there can be a large volume of space between the front row and the forward cabin structure presented facing the front row. It therefore can be unfeasible to mount an airbag in the traditional vehicle structure, i.e., the instrument panel and/or steering wheel. In fact, this may be the case for any seating position in the vehicle, especially with the proposition of seats <b>30</b> that can swivel as described above.

It therefore becomes evident that the various passenger seating configurations enabled by autonomous vehicles can present challenges to the conventional concepts of airbag protection. Furthermore, since airbags require structure supporting the deployed airbag against movement in response to occupant penetration (e.g., a reaction surface), the absence of typical vehicle architecture that acts as a reaction surface presents additional challenges.

The occupant safety system <b>100</b> shown in <figref idref="DRAWINGS">FIGS. 1-5</figref> includes at least one vehicle occupant protection device in the form of an inflatable airbag <b>120</b> mounted in the roof <b>58</b> of the vehicle <b>20</b>. Mounting the airbags <b>120</b> in the vehicle roof <b>58</b> is convenient because the airbags can be positioned in a location with a desired proximity to the occupant(s) <b>10</b> they are intended to help protect. This can help reduce the necessary inflatable volume of the airbags <b>120</b> and can also help provide a desired airbag deployment time without requiring an excessively high-volume inflator.

The airbags <b>120</b> are housed/concealed in the roof structure of the vehicle <b>20</b> behind, for example, a roof liner <b>60</b>. The airbag <b>120</b> is rolled/folded and packaged, e.g., in a sheath or housing <b>121</b>, before being placed behind the roof liner <b>60</b>. An inflator <b>130</b> is operatively connected to the airbag <b>120</b> and is actuatable to provide inflation fluid for inflating the airbag. The inflator <b>130</b> can be of any known type, such as stored gas, solid propellant, augmented or hybrid. The packaging/housing <b>121</b> can also contain or otherwise support the inflator <b>130</b>.

The airbag <b>120</b>, inflator <b>130</b>, and any associated packaging or housing <b>121</b> can form an airbag module <b>140</b> that can be installed in the roof <b>58</b> as a unit. An airbag module <b>140</b> can, for example, be installed above each seat <b>30</b> of the vehicle, i.e., on a per seat basis. The occupant safety system <b>100</b> can therefore include multiple airbags <b>120</b> spaced about the vehicle roof <b>70</b> at locations associated and aligned with each seat <b>30</b>. In other words, each seat <b>30</b> in the vehicle <b>20</b> can have its own associated individual airbag module <b>140</b>.

The airbag <b>120</b> can be constructed of any suitable material, such as nylon (e.g., woven nylon 6-6 yarns), and may be constructed in any suitable manner. For example, the airbag <b>120</b> may include one or more pieces or panels of material. If more than one piece or panel is used, the pieces or panels can be interconnected by known means, such as stitching, ultrasonic welding, heat bonding, or adhesives, to form the airbag <b>120</b>. The airbag <b>120</b> can be uncoated, coated with a material, such as a gas impermeable urethane, or laminated with a material, such as a gas impermeable film. The airbag <b>120</b> can therefore have a gas-tight or substantially gas-tight construction. Those skilled in the art will appreciate that alternative materials, such as polyester yarn, and alternatives coatings, such as silicone, may also be used to construct the airbag <b>120</b>.

The system <b>100</b> also includes an airbag control unit (ACU) <b>150</b> that is operable to actuate the inflator(s) <b>130</b> in response to a vehicle crash. The ACU <b>150</b> is a central controller that communicates with one or more crash sensors (not shown) in order to determine the occurrence of a vehicle crash for which occupant protection is desired. The ACU <b>150</b> is operable to actuate the inflators <b>130</b> in response to detecting the vehicle crash.

Upon sensing the occurrence of an event for which inflation of the airbag <b>120</b> is desired, such as a vehicle collision, the ACU <b>150</b> provides an actuation signal to the inflator <b>130</b>. Upon receiving the signals from the ACU <b>150</b>, the inflator <b>130</b> is actuated and provides inflation fluid to the inflatable volume of the airbag <b>120</b> in a known manner. The inflating airbag <b>120</b> exerts a force on the roof liner <b>60</b>, which causes the roof liner to open (e.g., via tear seam or door) and release the airbag <b>120</b> to inflate and deploy from the stored condition (<figref idref="DRAWINGS">FIGS. 1 and 4</figref>) to the deployed condition (<figref idref="DRAWINGS">FIGS. 2 and 5</figref>). The airbag <b>120</b>, while inflated, helps protect the vehicle occupant <b>10</b> by absorbing impacts with the occupant and cushioning the occupant's movement in response to the crash.

As shown in <figref idref="DRAWINGS">FIGS. 2 and 5</figref>, the airbag <b>120</b>, when inflated and deployed, encircles the occupant <b>10</b> and the seat <b>30</b>, particularly the seatback <b>36</b>. The seatback <b>36</b> can therefore act as a reaction surface for supporting the airbag <b>120</b> against movement in response to a vehicle crash and the resulting occupant movement into engagement with the airbag. This allows the airbag <b>120</b> to absorb forces associated with the impacting occupant <b>10</b>, which helps cushion and protect the occupant. In fact, as described and illustrated below, the vehicle seat <b>30</b>/seatback <b>36</b> acts as the primary reaction surface for supporting the airbag <b>120</b> against occupant impact forces in a variety of crash scenarios.

An example configuration of the airbag <b>120</b> alone, without the surrounding vehicle structure, occupant, and other components of the safety system, is shown in <figref idref="DRAWINGS">FIG. 3</figref>. The airbag <b>120</b> includes an upper portion <b>122</b> and a lower portion <b>124</b>. The lower portion <b>124</b> is connected to the upper portion <b>122</b> by pillars <b>126</b>. In the example configuration of <figref idref="DRAWINGS">FIG. 3</figref>, the airbag <b>120</b> includes four pillars <b>126</b> that extend between the upper and lower portions <b>122</b>, <b>124</b>. The airbag <b>120</b> could, however, include a different number of pillars, either greater than or less than four. The lower portion <b>124</b> defines a lower opening <b>160</b> of the airbag <b>120</b>. The pillars <b>126</b> define openings or windows <b>162</b> of the airbag <b>120</b>.

The upper portion <b>122</b> anchors the airbag <b>120</b> to the vehicle roof <b>58</b>. The lower portion <b>124</b>, encircling the vehicle seat <b>30</b> and the occupant <b>10</b>, performs the primary occupant protection functions of the airbag <b>120</b>. The pillars <b>126</b> provide inflation fluid conduits, delivering inflation fluid to the lower portion <b>124</b> from the upper portion <b>122</b>, and can also provide some occupant protection functionality.

The inflator <b>130</b> can be centrally located in the upper portion <b>122</b> and can be configured to direct inflation fluid radially outward in a manner selected to deploy the lower portion <b>124</b> and pillars <b>126</b> in a desired manner. For example, the inflator <b>130</b> can be configured to deploy the lower portion <b>124</b> and pillars <b>126</b> in a uniform manner, such as uniformly downward from the vehicle roof <b>58</b>. Additionally, the upper portion <b>122</b> can also be configured to help divide and direct the inflation fluid into the pillars <b>126</b> in order to produce this desired deployment. To do this, the upper portion <b>122</b> can include internal tethers or seams that create flow channels that direct inflation fluid into the conduits <b>126</b> in a manner selected to produce the desired deployment characteristics.

The configuration of the lower portion <b>124</b> can be any desired configuration or shape selected to encircle the occupant <b>10</b> and the seatback <b>36</b>. The important characteristic of the configuration of the lower portion <b>124</b> is a confinement forming an inflated volume that encircles the occupant <b>10</b> and the vehicle seatback <b>36</b>. The lower portion <b>124</b> does not require uniformity in cross-section or shape, although it may be advantageous to possess one or both of these characteristics. The important characteristic of the lower portion <b>124</b> is that it has a tubular configuration that encircles the occupant <b>10</b> and the seatback <b>36</b>.

The closed tube configuration of the lower portion <b>124</b> can, for example, be generally toroidal. A “toroid,” by definition, is a surface of revolution with a hole in the middle, forming a solid body. The axis of revolution passes through the hole and therefore does not intersect the surface. The classic example of a toroidal shape is when a circle is rotated around an axis parallel to one of its edges, forming a doughnut shape referred to specifically as a “torus.” As another example, when a rectangle is rotated around an axis parallel to one of its edges, forming a hollow ring with a rectangular cross-section. From this, those skilled in the art will appreciate that the lower portion <b>124</b> can similarly be formed as hollow ring structures with cross-sections having various geometries, including regular and irregular shapes, polygons, etc.

By “generally toroidal,” it is meant that the configuration of the lower portion <b>124</b> is or approximates a toroidal surface revolution. The lower portion <b>124</b> can, for example, have the configuration of a torus. This configuration may not be precise, i.e., the configuration can, in general, be that of a torus, with the understanding that the shape can vary or have imperfections due to a variety of factors. For example, the lower portion <b>124</b> can depart from a purely toroidal shape at the intersections with the pillars <b>126</b>. As another example, the shape of the lower portion <b>124</b> can depart from a purely toroidal shape due to the woven and/or stitched together fabric construction of the airbag <b>120</b>. The configuration of the lower portion <b>124</b> can also depart from toroidal in that the ring, instead of having a circular shape, can be configured to take the shape of a rounded square, rectangle, pentagon, hexagon, or other geometric form. Further, inflation dynamics may cause the lower portion to distort from the toroidal shape during the inflation process and even while deployed. Interactions with the vehicle and/or occupant can also distort the shape of the lower portion <b>124</b>.

<figref idref="DRAWINGS">FIGS. 2 and 5</figref> illustrate the safety system <b>100</b> deployed in response to a vehicle crash that results in the occupant <b>10</b> moving forward from the vehicle seat <b>30</b>. The occupant movement is relative to the vehicle seat <b>30</b> and not necessarily the vehicle <b>20</b>, as the seat can be rotated on the swivel base <b>32</b>. In <figref idref="DRAWINGS">FIGS. 2 and 5</figref>, the forward movement of the occupant <b>10</b> relative to the vehicle seat <b>30</b> happens to coincide with forward movement of the vehicle <b>20</b>. <figref idref="DRAWINGS">FIGS. 2 and 5</figref> can therefore be illustrative of a vehicle frontal collision.

As shown in <figref idref="DRAWINGS">FIGS. 2 and 5</figref>, when the airbag <b>120</b> is deployed, the lower portion <b>124</b> encircles both the occupant <b>10</b> and the seatback <b>36</b>. The airbag <b>120</b> can be configured to position the lower portion <b>124</b> on or near the occupant's legs <b>170</b> and torso <b>172</b>, e.g., at or about the waist <b>174</b>. In response to the vehicle crash, the occupant <b>10</b> moves forward relative to the seat <b>30</b>, away from the seatback <b>36</b>, into engagement with the lower portion <b>124</b> of the airbag <b>120</b>. Restrained at the waist by a lap portion of the seatbelt <b>42</b>, the occupant <b>10</b> bends forward about the waist <b>174</b>, and his/her torso <b>172</b> bends or arches forward as shown. The occupant's upper torso <b>172</b> and head <b>176</b> can extend through the window <b>162</b> defined between the pillars <b>126</b>. The lower portion <b>124</b> restrains and cushions the occupant <b>10</b>, distributes impacts with the airbag <b>120</b> and provides a desired ride-down effect, i.e., a gradual deceleration of the forward-moving occupant.

The lower portion <b>124</b> is configured to receive the occupant <b>10</b> and conform or comply with the motion of the occupant in response to the vehicle crash. As shown in <figref idref="DRAWINGS">FIGS. 2 and 5</figref>, the cross-sectional shape of the lower portion <b>124</b> is shaped, i.e., round or rounded, and sized, i.e., diameter/cross-sectional area so that the lower portion both engages the occupant's torso <b>172</b> and receives the occupant's head <b>176</b>. The shape of the lower portion <b>124</b> matches or resembles the natural forward arching of the occupant <b>10</b>, restrained by the lap belt portion, while at the same time cushioning, distributing impact forces, and providing the desired ride-down effect.

Advantageously, the configuration and/or cross-sectional shape of the lower portion <b>124</b> can be selected to match or enforce a natural position of the occupant <b>10</b>. This position can be that of an occupant having a physiology selected according to statistics that place that person within certain segments of the population. The lower portion <b>124</b> can, for example, be configured to match or resemble the physiology of an occupant sized according to National Highway Transportation Safety Administration (NHTSA) guidelines, such as a 50^thpercentile male occupant, a 95^thpercentile male occupant, or a 5^thpercentile female.

Because the lower portion <b>124</b> encircles the seatback <b>36</b>, the seatback restricts movement of the airbag <b>120</b> in response to receiving the impacting occupant <b>10</b>. As the occupant <b>10</b> moves into engagement with the lower portion <b>124</b>, the lower portion moves with the occupant away from the seatback <b>36</b>. The portion of the lower portion <b>124</b> extending behind the seatback <b>36</b> engages the seatback, which restrains the lower portion from further movement. The seatback <b>36</b> acts as a reaction surface that supports the airbag <b>120</b> so that it can protect the occupant <b>10</b> by absorbing and distributing the forces associated with the occupant striking the airbag.

The vehicle roof <b>58</b> can also serve as a reaction surface for the airbag <b>120</b>. Through the attachment of the upper portion <b>122</b> to the roof <b>58</b>, the pillars <b>126</b> can become tensioned in response to the occupant <b>10</b> engaging and exerting forces on the lower portion <b>124</b>. For example, viewing <figref idref="DRAWINGS">FIGS. 2 and 5</figref>, while the impact forces exerted on the lower portion <b>124</b> by the occupant <b>10</b> are primarily in the forward direction, it can be seen that the occupant also exerts some downward force on the lower portion due to their arching or bending forward motion. The roof <b>58</b> acts as a reaction surface against these vertical components of the occupant impacts with the airbag <b>120</b>. The function of the roof <b>58</b> as a reaction surface can therefore be seen as secondary, as the seat <b>30</b>/seatback <b>36</b> acts as the primary reaction surface for the airbag, particularly the lower portion <b>124</b>.

Advantageously, because the lower portion <b>124</b> encircles the occupant <b>10</b> and has a uniform cross-sectional configuration (e.g., generally toroidal, see above), the airbag <b>120</b> can offer the occupant <b>10</b> a 360-degree level of protection. Because the swivel base <b>32</b> can allow the occupant to be facing in a 360-degree user-selected position, vehicle crashes can result in the occupant moving, relative to the seat <b>30</b> in directions that vary from the forward direction illustrated in <figref idref="DRAWINGS">FIGS. 2 and 5</figref>. Additionally, even where the occupant <b>10</b> is seated in a forward-facing position, certain types of vehicle crashes can result in the occupant's moving in directions lateral to the vehicle seat <b>30</b> and/or forward direction.

By directions “lateral to the vehicle seat,” it is meant to refer to movement at an angle relative to a front facing surface of the seat <b>30</b>. The front facing surface of the vehicle seat <b>30</b> can be considered to be the surface of the seatback <b>36</b>. Front facing, in this regard, is meant to refer to perpendicular to the seatback <b>36</b> and within the lateral confines of the seat. Movement in directions lateral to the front facing surface of the vehicle seat <b>30</b> would be diagonal movement forward of the seatback <b>36</b> and either to the right or to the left of the vehicle seat. For a forward facing vehicle seat <b>30</b>, movements in directions lateral to the vehicle seat <b>30</b> would be forward and either inboard or outboard of the vehicle <b>20</b>.

These lateral occupant movements can result from various crash scenarios. For example, lateral occupant movements can result from angular collisions—where the vehicle <b>20</b> and/or the object struck by the vehicle are travelling at an angle relative to each other. Lateral occupant movements can also result from offset collisions, where the vehicle <b>20</b> and/or the object struck by the vehicle are travelling parallel to each other, but their center of masses are offset from each other. Lateral occupant movements can also result from side impact collisions, where the vehicle <b>20</b> strikes or is struck from the side. Lateral occupant movements can also result from frontal collisions, or any type of collision for that matter, where the seat <b>30</b> is rotated away from the forward facing position.

The airbag <b>120</b> is configured to help protect the occupant <b>10</b> in any crash scenario where the occupant <b>10</b> moves laterally relative to the seat <b>30</b>. <figref idref="DRAWINGS">FIGS. 6-8</figref> illustrate examples of these crash scenarios. <figref idref="DRAWINGS">FIG. 6</figref> illustrates a crash scenario where the seat <b>30</b> and occupant <b>10</b> are forward facing in the vehicle. <figref idref="DRAWINGS">FIG. 7</figref> illustrates a crash scenario where the seat <b>30</b> is rotated 90-degrees from forward, i.e., facing inboard or outboard. <figref idref="DRAWINGS">FIG. 8</figref> illustrates a crash scenario where the seat <b>30</b> is rotated 45-degrees from forward, i.e., facing 45-degrees inboard or outboard. In <figref idref="DRAWINGS">FIGS. 7-8</figref>, the forward and rearward directions in the vehicle are indicated by arrows labeled as such.

Referring to <figref idref="DRAWINGS">FIG. 6</figref>, it can be seen that the occupant <b>10</b> of the forward facing seat <b>30</b> moves into engagement with the airbag <b>120</b> in an lateral direction. This can, for example, be the result of an angular or offset vehicle collision. In this crash scenario, the airbag <b>120</b> offers several advantages. Since the lower portion <b>124</b> surrounds the occupant <b>10</b>, it is positioned to receive the occupant, and is configured to coincide with the leaned or bent forward condition of the occupant. The lateral movement of the occupant <b>10</b> pulls on the lower portion <b>124</b> in a different, i.e., lateral, direction, does not deter the seatback <b>36</b> from acting as a reaction surface, along with the roof <b>58</b> via the pillars <b>126</b>.

Additionally, in <figref idref="DRAWINGS">FIG. 6</figref>, the lateral movement of the occupant <b>10</b> can result in the occupant, especially the occupant's head <b>176</b>, being received at the intersection or junction <b>128</b> of the lower portion <b>124</b> and a pillar <b>126</b>. Advantageously, the pillar <b>126</b> can help provide additional restraint of the occupant <b>10</b> against lateral, inboard/outboard movement. The pillar <b>126</b> can also serve to cushion the occupant <b>10</b> against impacts with adjacent vehicle structure, such as the side structure <b>52</b> (in the case of lateral outboard occupant movement) or a center console or adjacent seat/occupant (in the case of lateral inboard occupant movement).

Referring to <figref idref="DRAWINGS">FIG. 7</figref>, the occupant <b>10</b> of the 90-degree rotated seat <b>30</b> moves laterally relative to the seat, in this case laterally, as indicated generally by the arrow, into contact with the airbag <b>120</b>. <figref idref="DRAWINGS">FIG. 7</figref> is thus illustrative of the occupant <b>10</b> of the 90-degree seat <b>30</b> being involved in a vehicle frontal collision, so the lateral movement of the occupant coincides with the forward direction in the vehicle. The occupant <b>10</b> moves in this lateral direction into engagement with the airbag <b>120</b>. In this crash scenario, the airbag <b>120</b> offers several advantages. Since the lower portion <b>124</b> surrounds the occupant <b>10</b>, it is positioned to receive the occupant, and is configured to coincide with the leaned or bent condition of the occupant. The seatback <b>36</b>, along with the roof <b>58</b> via the pillars <b>126</b>, act as a reaction surface for the airbag <b>120</b>.

In the 90-degree rotated seat crash scenario of <figref idref="DRAWINGS">FIG. 7</figref>, the occupant <b>10</b>, restrained at the waist <b>174</b> by the lap portion of the seatbelt <b>42</b>, leans and or bends laterally. Lateral bending of the torso <b>172</b> and head/neck <b>176</b> is unnatural once the degree of bending goes beyond a certain extent. Advantageously, as shown in <figref idref="DRAWINGS">FIG. 7</figref>, the airbag <b>120</b> can be configured such that a pillar <b>126</b> is positioned to receive, or at least partially receive, the occupant <b>10</b> in this crash scenario. When this occurs, the pillar <b>126</b> not only helps cushion the occupant <b>10</b>, but also helps prevent extreme lateral bending of the occupant. The pillar <b>126</b> can also serve to cushion the occupant <b>10</b> against impacts with adjacent vehicle structure or occupants. As the crash proceeds, the occupant <b>10</b> can be received in and cushioned by the junction <b>128</b> between the lower portion <b>124</b> and the pillar <b>126</b>.

Referring to <figref idref="DRAWINGS">FIG. 8</figref>, the occupant <b>10</b> of the 45-degree rotated seat <b>30</b> moves laterally relative to the seat, in this case at a 45-degree angle relative to the seat, as indicated generally by the arrow, into contact with the airbag <b>120</b>. <figref idref="DRAWINGS">FIG. 8</figref> is thus illustrative of the occupant <b>10</b> of the 45-degree seat <b>30</b> being involved in a vehicle frontal collision, so the lateral movement of the occupant coincides with the forward direction in the vehicle. The occupant <b>10</b> moves in this lateral/angled direction into engagement with the junction <b>128</b> between the lower portion <b>124</b> and the pillar <b>126</b>. In this crash scenario, the airbag <b>120</b> offers several advantages. Since the lower portion <b>124</b> surrounds the occupant <b>10</b>, it is positioned to receive the occupant, and is configured to coincide with the leaned or bent condition of the occupant. The seatback <b>36</b>, along with the roof <b>58</b> via the pillars <b>126</b>, act as a reaction surface for the airbag <b>120</b>.

In the 45-degree rotated seat crash scenario of <figref idref="DRAWINGS">FIG. 8</figref>, the occupant <b>10</b>, restrained at the waist <b>174</b> by the lap portion of the seatbelt <b>42</b>, leans and or bends laterally, i.e., at an angle both forwardly and laterally. Advantageously, as shown in <figref idref="DRAWINGS">FIG. 8</figref>, the airbag <b>120</b> can be configured such that the lower portion <b>124</b> initially receives and restrains the occupant <b>10</b>. Depending on the severity of the crash scenario, further movement and penetration of the occupant into the lower portion <b>124</b> will result in the occupant moving or sliding along the lower portion into the junction <b>128</b> and engages the adjacent pillar <b>126</b>. When this occurs, the pillar <b>126</b> helps cushion the occupant <b>10</b> against impacts with adjacent vehicle structure or occupants.

From the above, it will be appreciated that the example configurations of <figref idref="DRAWINGS">FIGS. 1-8</figref> illustrate that the airbag <b>120</b> is configured to utilize the vehicle seat as the primary reaction surface for crash scenarios involving both conventional and unconventional seating arrangements. By “reaction surface,” it is meant that it is the vehicle roof and the vehicle seat support the airbag against movement in response to an impacting occupant. In other words, the airbag attempts to move in a first direction and the roof and/or vehicle seat applies a reaction force to the airbag in a second, opposite (or substantially opposite) direction to limit/prevent movement of the airbag in the first direction. This allows the airbag to absorb impact forces of the occupant and provide the desired ride-down effect.

Advantageously, the example configurations can require only the vehicle roof and seat to provide the reaction surface and can provide effective occupant protection without requiring any support from structure presented forward of the occupants. In other words, the airbag need not deploy between the occupant and any particular vehicle structure so that the structure can support the airbag for occupant penetration. The vehicle roof and seat can support the airbag module and the airbag entirely. In certain example configurations, and under certain vehicle crash conditions, portion(s) of the airbag could come into contact with vehicle structure other than the roof/seat, such as a side window, that could act as an additional reaction surface. The point is, however, that this additional reaction surface is not necessary or required.

What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. For example, although the vehicle safety system is described herein as being implemented in a vehicle with swivel base seats, the safety system can be implemented in a vehicle with fixed (e.g., forward facing) seats. Additionally, although the safety system is described herein as being implemented in a vehicle with one airbag per seat, the system can be implemented in a vehicle with one airbag per multiple seats (e.g., bench seating). Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.